When Sara Sheridan's daughter Molly was a child, the mystery novelist would spin fantastical stories to keep her entertained and pass on a life lesson or two in the process.

Now the pair have teamed up to write a new children's book that they hope will inspire others to view the world around them differently.

For Sara, 50, the author of the bestselling Mirabelle Bevan mysteries, penning Monsters Unite with her 27-year-old make-up artist daughter was "really good fun."

She said: "Molly's memory of the stories were slightly different from my memory of them, which was interesting."

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The book follows the adventures of Nessie, a shy Loch Ness monster, who, with the help of a network of underwater tunnels, recruits a team of Monster friends to fight the plastic pollution that threatens their environment.

A story about "sustainability and cooperation", Monsters Unite morphed from a childhood allegory to a physical picturebook after Sara bumped into publisher and children's author Alan Windram at the Islay Book Festival.

She said: "Talking to Alan about how important to tell your kids stories so they can pick up skills turned into him offering to publish it."

There is an accidental political message embedded into the tale too, says Sara: "Twenty years ago when I made it up it wasn't a Brexit fable but nowadays it kind of is as it's all aboout cooperating with monsters all over Europe and everyone working together - which I think is a great thing to teach your kids."

The Herald: Molly and Sara with Alan WindramMolly and Sara with Alan Windram

The picture book was illustrated by Iain Carroll, a "monster obsessive" whose attention to detail brought Sara and Molly's imagined world to life.

The adventures of Nessie was just one of Sara's tales. Molly's Barbie doll took on a secret life as a stereotype-smashing spy while a family of misfortunate characters who battled against the odds still inspire her daughter when times are troubled.

Sara said: "There was a family called the Optimistic Murrays who always had terrible things happen to them but they dealt with it really well - the washing machine floods, or one of the kids go missing and they just roll up their sleeves and get on with it.

"Molly says that even now if a train gets cancelled or something she thinks, right, what would the optimistic Murrays do?"

Monsters Unite is not the first collaboration between the mother-daughter duo who run perfume brand Reek together but writing the book was something special.

Sara said: “It was a really nice thing to do together. It was lovely to have our own private thing to share [when Molly was little]. It was just fun really. Something might have happened at school or with a friend and I told her a story that would help her with that.

“Teaching kids to look at things from the other side is really important and brings them up to be open minded. Good story books do that for parents and help kids to look at problems differently - it’s a way of communicating without being heavy handed about it.”

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But Sara, who has written more than twenty fiction and non-fiction books, is not about to stop creating worlds of escape for adults anytime soon.

The Herald: Nessie fights plastic pollution in Monsters UniteNessie fights plastic pollution in Monsters Unite

She said: “I’m definitely an adult writer. I made up theses stories for Molly and I just loved telling stories for my own nieces and nephews and god-children and getting them to think about something they might not have otherwise considered.

“I think it’s important for adults to think about books made for kids and the value of them. People know they should be reading [to their children] but they don’t necessarily understand what it brings to their family.

"I would love it if parents loved Monsters Unite too.”

Buy your copy of Monster Unite here.